The present invention relates to a server system of a type wherein the sharing of resources can be carried out using extensions of a private branch exchange (PBX), and more specifically to a system for and a method of exchanging server data in a packet unit, of a type wherein a plurality of users can simultaneously utilize the same resource.
As one of conventional arts, there is known one disclosed in Japanese Patent Application Laid-Open No. 1-109847. According to the disclosure, peripheral devices such as a printer, hard disc are electrically connected to an exchange network of a digital exchanger through a data interface unit. On the other hand, a data processing unit is electrically connected to the exchange network of the digital exchanger through a data access unit. In the conventional art having such an arrangement, terminals are electrically connected to the data processing unit and the peripheral devices (servers) by making use of exchange functions of the digital exchanger. The digital exchanger is provided with connecting shared buses for the purpose of control of the peripheral devices. The buses are interconnected to internal buses of a data processing control device. When a plurality of peripheral devices are connected to the exchange network, the data processing control device can accept operation requests of other peripheral devices while one peripheral device is in operation. Thus, the data processing control device connects a line for a peripheral device to which a use request has been made to a line for a corresponding peripheral device. According to the prior art, as described above, a plurality of peripheral devices can simultaneously be utilized by connecting the peripheral devices to separate lines.
The above disclosure does not take into consideration a case where use requests are made to the same peripheral device from a plurality of terminals (lines). When one terminal makes use of the peripheral device, other terminals cannot use it, with the result that they had to wait for its use until a process of the terminal while being using the peripheral device is completed.
In the above prior art, the data processing unit needs dedicated control buses in order to control the peripheral devices. It is necessary to place connection terminals used to connect the peripheral devices to the exchange network and extending from the data interface unit, and the control buses in all possible places where the peripheral devices can be disposed. In order to ensure that users can freely travel over the peripheral devices, it is thus necessary to provide data interface units in the digital exchanger by the number of possible places where the peripheral devices can be placed. It is also necessary to place connection terminals extending from data interface units and control buses in all possible locations where the peripheral devices can be disposed. Thus, there was need for the provision of excessive equipment.
The above prior art does not give consideration as to the fact that a user travels over the peripheral devices so as to be connected to another line. Thus, when the user travels over the peripheral devices so as to change a connection line, a table indicative of the corresponding relation between numbers of the connection terminals for the connection of the peripheral devices, which numbers being held by the digital exchanger and practically-connected peripheral devices, was rendered necessary to be rewritten by either a user or a system controller. It was also necessary to inform all the users who make use of the peripheral devices of a connection line number change message.
In addition, the above prior art does not give consideration as to the security against information stored in disc devices. When a message relative to a line number to which a peripheral device is connected is received, a response to a connection request was made without reserve.